an NSF-sponsored center for nanoscale science and engineering

Nanoscale Sensing, Positioning and Fabrication

• Develop a low cost open-air microscale manufacturing process that will permit inexpensive manufacturing in a research laboratory, factory, or classroom environment.

• Develop finite element model of micro-groove cutting process.• Demonstrate the ability to cut selected microscale features.• Support Nano-CEMMS manufacturing needs.

Goals

Manufacturing of Multi-Scale Freeform Grooves Using a Micro-Scale Machine Tool

Professor Richard E. DeVor and Professor Shiv G. Ka poorGraduate Student: Keith Bourne

Mapping to Center’s Objectives

Fundamental Questions/Challenges

Research Plan

Broader Impact

Future Efforts

• Develop a rapid and inexpensive micro-groove cutting process for cutting arbitrary patterns of grooves with micron to submicron cross-sections and meso-scale lengths.

• Cost effective technology for the manufacture of precision meso-scale components with micro-scale grooves.

• Other research groups can machine experimental devices with highly detailed patterns of grooves.

• Development of process and suitable machine tool topology.• Effect of variations in cutting conditions and tool geometry on

groove geometry and tool life.• Modeling cutting mechanics at submicron scale.

Research Results

• Develop suitable tool geometries.• Develop finite element model of the process.

• Microfluidic devices• Engineered Surface Textures• Optical features

• Free-form curvilinear patterns• Large workpiece area (12.25 cm2)

• Fast cutting speeds• Open-air micro-machining

• Embossing mold production• Micro-forming dies• Lithography mask fabrication• Micro-heat exchangers

Developed Rectangular Groove Cutting Capabilities• Well formed rectangular grooves with steep sidewalls.

Developed Compound V-Groove Cutting Capabilities

2.7

� Design, construct, and test a micro-groove cutting device. � Use commercial AFM probes as tools in order to gain an

basic understanding of how cutting speed, cutting load, and tool geometry effect the micro-groove cutting process.

� Develop cutting tools suitable for micro-groove cutting.� Simulate micro-groove cutting process using finite element

analysis and determine ways of improving the process.

Tool Fabrication• Tools fabricated by modifying

diamond AFM probes via FIB.• Four thru cuts• Each cut made into the poster to

remove the gray shaded sections.• 50 – 64 nm edge radii achieved.

Micro-Groove Cutting Device

• 35 x 35 x 35 mm of XYZ-stage travel. • 20 nm linear resolution

Laser displacement sensor measures tool cantilever deflection with 10 nm resolution.

• Rotary B and C-stages• 0.316 acrsec rotary resolution

• Variable tool orientations• Arbitrary cutting speeds

Micro-Groove Cutting Process

• Depth of cut is function of cutting load, tool geometry, and workpiece material.

• Cantilever is bent to apply a load to a cutting geometry.

• Bending is measured and controlled by feedback.

• Workpiece is traversed under the tool to form a chip.

Cutting action

• Flexible single-point diamond cutting tools

• Diffraction grating fabrication.• Fabrication of long densely packed

microfluidic channels.

• Negligible tool wear when cutting at least 200 mm in aluminum.

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� Developed Curvilinear Groove Cutting Capabilities

• Micro-optics applications such as LCD backlight light guides.

• Tools can be fabricated to cut nearly arbitrary cross-sections.

• Target groove cross-sections achieved with very little burr formation.

Target Cross-section

• Continuous spiral shaped grooves with 3 µm spacing and 82 mm length.

Tightly Packed Groove Cutting Capabilities• Fabrication of high-density micro-heat exchangers.• Rectangular grooves 1 µm wide have been spaced

as closely as 0.75 µm apart.

• Grooves as narrow as 300 nm but over 2 µm deep.

411 nm wide tool 300 nm wide

groove

Tool Rake Face

Groove Geometry

• Grooves up to 2 µm deep• Good reproduction of tool profile.

Intersecting Groove Cutting Capabilities

1.1 mN50 mm/minSide View Top View

Cutting Edge

0.5 µµµµm deep grooves intersecting

• Required for microfluidics and surface patterning applications.

• Small exit burr if intersecting grooves are less than 0.5 µm deep.

• Burr reduction strategies must be developed for deeper grooves.

Result